View alignments
Since an alignment is a display of several sequences arranged in rows, the basic options for viewing alignments are the same as for viewing sequences. Therefore we refer to View sequences for an explanation of these basic options.
However, there are a number of alignment-specific view options in the Alignment info and the Nucleotide info in the Side Panel to the right of the view. Below is more information on these view options.
Under Translation in the Nucleotide info, there is an extra checkbox: Relative to top sequence. Checking this box will make the reading frames for the translation align with the top sequence so that you can compare the effect of nucleotide differences on the protein level.
The options in the Alignment info relate to each column in the alignment:
- Consensus. Shows a consensus sequence at the bottom of the
alignment. The consensus sequence is based on every single
position in the alignment and reflects an artificial sequence which
resembles the sequence information of the alignment, but only as one
single sequence. If all sequences of the alignment is 100%
identical the consensus sequence will be identical to all sequences
found in the alignment. If the sequences of the alignment differ the
consensus sequence will reflect the most common sequences in the
alignment. Parameters for adjusting the consensus sequences are
described below.
- Limit. This option determines how conserved the sequences must be in order to agree on a consensus. Here you can also choose IUPAC which will display the ambiguity code when there are differences between the sequences. E.g. an alignment with A and a G at the same position will display an R in the consensus line if the IUPAC option is selected. (The IUPAC codes can be found in the Appendix.) Please note that the IUPAC codes are only available for nucleotide alignments.
- No gaps. Checking this option will not show gaps in the consensus.
- Ambiguous symbol. Select how ambiguities should be displayed in the consensus line (as N, ?, *, . or -). This option has no effect if IUPAC is selected in the Limit list above.
- Conservation.
Displays the level of conservation at each position in the
alignment. The conservation shows the conservation of all sequence
positions. The height of the bar, or the gradient of the color
reflect how conserved that particular position is in the alignment.
If one position is 100% conserved the bar will be shown in full
height, and it is colored in the color specified at the right side
of the gradient slider.
- Foreground color. Colors the letters using a gradient, where the right side color is used for highly conserved positions and the left side color is used for positions that are less conserved.
- Background color. Sets a background color of the residues using a gradient in the same way as described above.
- Graph. Displays the conservation
level as a graph at the bottom of the alignment.
The bar
(default view) show the conservation of all sequence positions. The
height of the graph reflects how conserved that particular position
is in the alignment. If one position is 100% conserved the graph
will be shown in full height. Learn how to export the data behind the graph.
- Height. Specifies the height of the graph.
- Type. The type of the graph.
- Line plot. Displays the graph as a line plot.
- Bar plot. Displays the graph as a bar plot.
- Colors. Displays the graph as a color bar using a gradient like the foreground and background colors.
- Color box. Specifies the color of the graph for line and bar plots, and specifies a gradient for colors.
- Gap fraction. Which fraction of the sequences in the alignment that have
gaps. The gap fraction is only relevant if there are gaps in the alignment.
- Foreground color. Colors the letter using a gradient, where the left side color is used if there are relatively few gaps, and the right side color is used if there are relatively many gaps.
- Background color. Sets a background color of the residues using a gradient in the same way as described above.
- Graph. Displays the gap fraction as a
graph at the bottom of the alignment (Learn how to export the data behind the graph).
- Height. Specifies the height of the graph.
- Type. The type of the graph.
- Line plot. Displays the graph as a line plot.
- Bar plot. Displays the graph as a line plot.
- Colors. Displays the graph as a color bar using a gradient like the foreground and background colors.
- Color box. Specifies the color of the graph for line and bar plots, and specifies a gradient for colors.
- Color different residues. Indicates differences in aligned residues.
- Foreground color. Colors the letter.
- Background color. Sets a background color of the residues.
- Sequence logo.
A sequence logo displays the frequencies of
residues at each position in an alignment. This is presented as the
relative heights of letters, along with the degree of sequence
conservation as the total height of a stack of letters, measured in
bits of information. The vertical scale is in bits, with a maximum
of 2 bits for nucleotides and approximately 4.32 bits for amino acid
residues. See Bioinformatics explained: Sequence
logo for more details.
- Foreground color. Color the residues using a gradient according to the information content of the alignment column. Low values indicate columns with high variability whereas high values indicate columns with similar residues.
- Background color. Sets a background color of the residues using a gradient in the same way as described above.
- Logo. Displays sequence logo at the bottom of the alignment.
- Height. Specifies the height of the sequence logo graph.
- Color. The sequence logo can be displayed in black or Rasmol colors. For protein alignments, a polarity color scheme is also available, where hydrophobic residues are shown in black color, hydrophilic residues as green, acidic residues as red and basic residues as blue.